N-Doped Carbon Quantum Dot (NCQD)-Deposited Carbon Capsules for Synergistic Fluorescence Imaging and Photothermal Therapy of Oral Cancer

Abstract

Use of nanomaterials blessed with both therapeutic and diagnostic properties is a proficient strategy in the treatment of cancer in its early stage. In this context, our paper reports the synthesis of uniform size N-rich mesoporous carbon nanospheres of size 65−70 nm from pyrrole and aniline precursors using Triton-X as a structure-directing agent. Transmission electron microscopy reveals that these carbons spheres contain void spaces in which ultrasmall nitrogen-doped quantum dots (NCQD) are captured within the matrix. These mesoporous hollow NCQD captured carbon spheres (NCQD-HCS) show fluorescence quantum yield up to 14.6% under λ ex = 340 nm. Interestingly, samples calcined at >800 °C clearly absorb in the wavelength range 700−1000 nm and shows light-to-heat conversion efficiency up to 52%. In vitro experiments in human oral cancer cells (FaDu) show that NCQD-HCS are internalized by the cells and induce a substantial thermal ablation effect in FaDu cells when exposed under a 980 nm near-infrared laser.

New Insight into the Fluorescence Quenching of Nitrogen-Containing Carbonaceous Quantum Dots—From Surface Chemistry to Biomedical Applications

“…The quantum yield of the synthesized N-CQDs is about 17% relative to quinine sulfate (54% in 0.1 N H 2 SO 4 ). The value is typical for N-containing carbon quantum dots [ 29 , 30 , 31 ]. The 2D fluorescence topographical map ( Figure 2 e) of the N-CQDs shows one, though indistinct, contour appearing with an emission maximum in the range of 430–470 nm, depending on the excitation wavelength.…”

Progress of Nanomaterials-Based Photothermal Therapy for Oral Squamous Cell Carcinoma

“…It was found that the temperature of the NCOD-HCS solution at a concentration of 2 mg/mL would increase to 51 ℃ after exposure to a 980 nm laser for 15 min. After 5 min of 980 nm laser irradiation, the survival rate of FaDu cells treated with NCQD-HCS decreased significantly [ 84 ].…”

Advances in Cancer Therapeutics: Conventional Thermal Therapy to Nanotechnology-Based Photothermal Therapy

“…These nanospheres exhibited efficient fluorescence quantum yields and light-to-heat conversion property. When human oral cancer cells (FaDu) were treated with these nanospheres, they caused a significant thermal ablation to the cancer cells upon irradiation with a 980 nm NIR laser [ 155 ].…”